Observation of exceptional points in magnonic parity-time symmetry devices

• DOI: 10.1126/sciadv.aax9144
• Publication Date: 2019-11-23T00:17:16Z
• Authors: Haoliang Liu; Dali Sun; Chuang Zhang; Matthew Groesbeck; Ryan Mclaughlin; Z. Valy Vardeny
• Keywords: Parity (physics); Magnonics

Non-Hermitian Hamiltonians may still have real eigenvalues, provided that a combined parity-time (ƤƮ) symmetry exists. The prospect of ƤƮ has been explored in several physical systems such as photonics, acoustics, and electronics. eigenvalues these undergo transition from to complex at exceptional points (EPs), where the is broken. Here, we demonstrate existence EP magnonic devices composed two coupled magnets with different magnon losses. eigenfrequencies damping rates change crossing anti-crossing when coupling strength increases. dispersion includes strong "acoustic-like" mode weak "optic-like" mode. Moreover, upon microwave radiation, act resonant cavity unique response compared conventional systems.